Thermal Infrared Multimode Instrument
Information about the observations
Here are some useful general information concerning the observations.

10 microns data are acquired doing chopping and nodding.

Chopping is achieved moving the M2 mirror and nodding by moving the telescope.
     The maximum chopping amplitude is: 40" (recommanded), 60"(maximum possible).
     The maximum nodding amplitude up to 2' is possible
without guiding problems

In the acquisition programme, chopping and nodding angles are coded, with the same convention:
0 degree means from North to South and 90 degrees means from East to West.

The technical CCD used for guiding is equipped of two objectives

- large field: ~4arcminx6arcmin

- small field ~1arcminx1arcmin

Guiding is provided only on the small field: either though the dichroic or not

1/ if the science object is bright enough in the visible through the dichroic( < 14mag in R), it is used as "guide star"

2/ If within the dichroic FOV there is a bright enough object in the visible: it is used as 'guide star"

3/ If no bright enough object is available, the guide star is chosen off-axis from the dichroic using the large FOV.s


Send comments to <ls-infrared@eso.org>
Last update: 10 March 2001 
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